This is something I've been dreaming up in my spare time, and thought you tech guys over here at the Xprize forums might be able to help me out with this. This is what i've got so far; any ideas or constructive critizim would be greatly appreciated.

The concept is a highly reusable space shuttle that flies cheap and can land and take back off again in less than 20 minutes. It would take off like a plane, fly into the upper atmosphere at supersonic speeds, and then fire a rocket burn to push itself into the upper atmosphere. From there it would do its stuff, then fire a reverse burn to minimize its speed, and then slowly glide down to super sonic speeds, and then make a powered landing.

The technology involved is desinged to be based off of existing technology availibol and tested today. The aircraft will be enourmas, larger than the modern space shuttle. Its airframe will be modeled after that of the XB-70 Valkyrie, a large super-sonic bomber dating from the cold war, but will add lifting body technology from the X-24 technology demonstrators to maximize efficency.

It will take off from the ground like a normal aircraft, powered by either 6 high speed and high altitude turbofan jet engines (modeled after the massive engines used on modern airliners for the raw power nessairy to lift this off the ground and up into the upper atompshere) or 2 of the above mentioned turbofan engines and 4 (or possibly 6) Ramjet (or SCRAMjet) engines designed for high altitude and supersonic flight.

From here the craft would take off, and, despite its weight, climb to an altitude were jet engines would no longer operate. To aid in this, the craft would have enourmas wings and an unsually thick camber to provide maximum lifting capablity, paired with (as I mentioned before) lifting body technology, were the entire airframe itself would act as a wing to get the most out of the availbol surface area. Theres also aeronautical phenominon involved with the XB-70, which I'm not all that familier with, but to stay aloft it rides on a cusion of air. I would try to model as much after this as possible.

At an altitude were jet engines no longer were operable, this craft would orient itself to an angle of attack about 60 degrees up and administer a rocket burn to push itself to the altitude and velocity nessairy to reach an earth orbit (low or high). I don't know as much about rockets as I do jet engines, so I'm leaving the rockets as a wild card for now - unless you guys can think of a good ultra-high efficancy mixture or method realisticly usable on this spacecraft.

After its made its space operations (using a cargo bay roughly the size of the current space shuttle's), the spacecraft would align itself facing backwards, and fire a rocket burn to slow it down to a realistic speed were it wouldn't burn up, but wouldn't drop like a rock. Apon re-entry, a lot of different heat resisting methods would come into play. On the first layer would be some probably cyramic tiles with both extreme heat resistance and high duribility (so they don't need to be replaced every flight, hopefully more like every 20th flight - and so they dont brake if you drop something like a pidgeon on them). Something different may end up being used, but from what I know this is the most appealing outermost method. Inside a layer would be a series of titanium tubing containing a coolant that would act almost like 'blood' - cooling the outermost tiles so they don't melt. After this metal piping layer would come a perfectly smooth and strong heat resistant carbon fiber layer. This would be designed so that if a colombia incident did occour, the tiles and 'bloodstream' could be stripped off and the craft could continue to survive through its auxilarry carbon fiber hull. After this would come some basic insulation, and that would about wrap it up for heat resistance (might I add that this would also make a good meteor impact defense). The plane would not have to travel very on re-entry fast, and could use up a lot of speed, as it has still operable jet engines wich would probably be implimented for a powered landing at a wide variaty of landing strips.

I havn't made many sketchs of this, but I do have this:

Its the exact shape of the wing with some rough area shading for you to get an idea of were everything is on this thing.

EDIT: some random stuff I forgot; uh the wingtips would be curved downward, the main wings would carry compressed fuel in them, it uses a somewhat modified delta wing, I'm thinking of throwing some canards on the side of they can stand the heat, uh it has a crew 6 and can carry eight, the flight avianoics will, of course, be state of the art, maybe some new space suits for better space-walk operations.

just like to point out that it's probably not a good idea to call it "orion", as you'll see if you look around on several nuclear propulsion threads, or if you've read footfall (highly recommended if you haven't) .

Well... there is some. Jet liner turbofans aren't that great past transonic regime, supersonics would be impossible or very very difficult and very inefficient (both in fuel consumption and engine/duct arrangement aspects). J-58 is what you'd need.

The wingform and airfoil mismatch is another tough deal. The clipped/modified delta has very high induced drag at low speeds, while highly cambered airfoil do not perform well at high speeds. A variable-sweep variable-cambered wing would resolve the aerodynamic issue, but would be excessively heavy.

Also, you will be needing much more fuel on board, at mach 3 you've only accounted for about 1/8 of the required energy.

Well... there is some. Jet liner turbofans aren't that great past transonic regime, supersonics would be impossible or very very difficult and very inefficient (both in fuel consumption and engine/duct arrangement aspects). J-58 is what you'd need.

The wingform and airfoil mismatch is another tough deal. The clipped/modified delta has very high induced drag at low speeds, while highly cambered airfoil do not perform well at high speeds. A variable-sweep variable-cambered wing would resolve the aerodynamic issue, but would be excessively heavy.

Also, you will be needing much more fuel on board, at mach 3 you've only accounted for about 1/8 of the required energy.

The J-58 has a catch with it. The SR-71 funnels the supersonic shock wave into it, which with that cone generates a vaccume wich sucks the plane along at the ludicris speeds it can travel at - when its makin mach 3 or so its hardly got any weight on the throttle, as its heat generated from air resistance that dictates this planes maximum speed.

However, the jet did great getting the SR-71 up to altitude and up to the point were the nasselses and sucktion thingy took over, so that may still be a good choice. What I'm thinking is that this plane will be incredibly heavy at lift-off, so I would really need some moster engines to power the thing.... uh, if I was using J-58's or a direct variation I would either accomodate 4 classic turbofan engines, or bump that up to 8 or so J-58's.

Now, the wing shape... induce drag would be controlled by downard pointed wing tips, like that of the XB-70 Valkyrie (I did a bad job of drawing those, srry) - heres a picture (yes its a toy, but its the only good one showing the wing tips)

At least I think that minimizes induced drag.. well, if not high drag would be a plus.. on re-entry that is. I'm trying to minimize its take off distance, thats the main issue.

As for the airfoil itself, flying up at supersonic speeds a thick camber in the wings may not be as effective, but it is much more nessairy down at the runway on take off - this will be one heavy bird! Plus, I have a lot of wing area and the (did I mention this before?) fusulage of the ship also acts as a wing, using lifting body technology. If worst comes to worst, I may end up 'morphing' the camber, maybe raising the wing tips which would have a lot less camber in them than the main wing.

Also, to tie into your next point, heavy camber (and resultantly thick) wings
would provide more room for much needed fuel storage. The upper part of the wing would serve to store fuel for the jet engines, the lower wing and area directly behind the cargo bay would store fuel for the rocket engines.

You may remark that only one eigth the speed has been accounted for, but again a rocket burn would in place after that, and with one eigth in momentum and a lot less gravity up in the upper reaches of the atmosphere, a rocket burn would be much more effective. If nessairy, I can stretch out that last portion of the craft a lot more; along side the fuel storage is the part of the wing with the most area, alogn with the fact that the fuel area would be creating lift itself as a lifting body airfoil, all of which would hopefully make up for the added weight.

I'm hoping all the fuel required to get up into space this way would be a lot less than what is required for the current craft, given that we make use of brenulies principle, which would, hopefully, account for many hundreds (if not thousands) of pounds of fuel.

If I got something wrong up there, please tell me, I'm not quite as familier with some of this stuff as I am with other things.

EDIT: notice, on the valkyrie there are canards that pull the nose into the air and hold it aloft. Given we have stronger structural engineering today, we may not need that as much, but it may end up being a must, and if so I'm thinking of putting some canards in line with the very bottom of the nose, as to eh keep it and the nose from buring off on re-entry.

J-58 does not produce a vaccum to pull the plane along; in fact, it must bleed air like heck to keep running. The cones are there to control the compression and decompression shocks, which would flame out the engines uncontrolled.

Downward pointed wingtips do reduce the induced drag, in the magnitude of 5-10%. It would still have enormous induced drag.

A high-cambered wing would not sustain flight above mach one. The plane would have to rely entirely on thrust.

I wonder where I got the 1/8 figure. Actually, you've only covered about 1.1% of the required energy. The kinetic energy is proportional to the velocity squared.

Also, the gravity at 30 km is 99.1% of that on sealevel. The gravitational force between masses is inversely proportiional to the distance fo the masses squared. The radius of the earth is approximately 6378 km.

Bernoulli principle has little to do with flying. Bernoulli principle will also not work in compressible flow.

Edit: typo correction.

Last edited by Vendigo on Wed Sep 29, 2004 4:29 pm, edited 1 time in total.

Len Cormier had a design, IIRC, that surfed the stratosphere rather like that, but IIRC, it was designed to go from point A to B very quickly, rather the just take suborbital trajectories. I think it was purely rocket powered rather then two different propulsion systems.

I know Pioneer is still working on it, but turbines are just dead ballast once you run out of air. A SSTO or even an SSTsO needs to make maximum use of its mass.

Bernoulli principle has little to do with flying. Bernoulli principle will also not work in compressible flow.

Whoa.. think about what you just said there! Bernoulli's principle is the entire basis for flight, is it not? Gah...

As for the airfoils, If nessairy, I guess I would thin the camber over all the wing that would have been used for fuel storage, but I would hope the camber over the jet engines and the fusulage would be enough to get the plane to take off at liftoff.

Concerning induced drag, the XB-70 has found a way to fly despite its enourmas mass and delta wings, so 30 years later we should be able to make this happen with a space shuttle of a simlear format...

And as for that lack of energy before the rocket burn, I'm curious how much fuel would be required to achive that needed energy, and whether verticly launched conventional rockets spend more fuel reaching into space through the air, or trying to reach the nessairy amount of energy to enter an earth orbit. Either way, something I forgot before is that up were air breathing engines no longer operate, rocket burns become a lot more effective (given the lack of air in the way).

Now, to conserve weight I heard somebody mention something about jet engines wich could be converted to rocket motors (like in flight) - these, if efficent enough (both in jet and rocket stage), could possible conserve considerable weight and space... then again, rocket motors tend to be very simple and small, as its the fuel that really takes up the space from what I know... [/i]

bournelli's principle doesn't apply to transonic fluid flow around an object, becasue of shockwave formation. Density isn't constant at that point, but stabilizes after this.

Pardon my lack of knowledge on the matter, but if bournellis principle doesnt keep a plane in the air at supersonic speeds, than what does?And wouldnt the transonic fluid be only momentary, to be replaced by full supersonic 'fluid'? And doesnt the shockwave origionate at the nose, staying out of the way of swept wings, resulting in no shockwaves messing with the airfoil? And how could controls even work with no lift in effect? The entire purpose of an airleon/flap is to increase the camber of an airfoil to generate increased lift (or destroy the camber, causing a lack of lift), is it not? This is all a bit disconcerting...

I retract my words of Bernoulli having little to do with flying. Bernoulli has practically nothing to do with flying. A regular Cessna would need an airspeed in excess of 400mph to stay aloft with the pressure differential. Angle of attack keeps the plane airborne. It's a stupid myth that bernoulli principle would be the prime source of lift.

As for the induced drag, XB-70 did not have to worry about that. Induced drag occurs at low speeds, and after that, all it had was the little profile drag from the thin, plate-like wings (symmetric profile on both upper and lower side of the wing; there goes the bernoulli out the window again). On the other hand, your wing design is MISMATCHED. It has all the same induced drag as XB-70, but because of the thick wing, it has high profile drag as well. Same goes for lifting body section. It's excessively draggy in ALL flight regime, unlike XB-70 which had high drag only during take-offs and landings.

Air resistance is of little concern when going for orbit. The required speed is 8 kilometers per second. Most of the acceleration is done outside atmosphere anyway.

I have no interest in having a further quarrel of how things are vs. how you would like them to be. If reality doesn't suit you, write Sci-fi instead.

Last edited by Vendigo on Wed Sep 29, 2004 8:54 pm, edited 2 times in total.